In drum type rotary mowers currently in use the rotatable drum cutter units comprise cylindrical bodies mounted beneath a transversely-extending main beam and having annular flanges at their lower ends for pivotally supporting cutter blades. These cutter units are driven from the top and, therefore, the drive means may be arranged inside the main beam. At the lower end, ground-engaging supports are normally arranged underneath each of the cutting units for supporting the structure on the ground. These ground-engaging supports may be stationary units or may be freely rotatable. Crop engaging and discharging ribs may protect from the upper side of the flanges and/or the outer circumference of the cylindrical body portions. The drums normally are driven at a very high speed such as in the range of 2000 to 2500 r.p.m. Exemplary of this type of mower are the machine shown in U.S. Pat. No. 3,389,539 issued on June 25, 1968, and U.S. Pat. No. 3,443,369 issued on May 13, 1969.
Drum mowers are generally well accepted because in certain crop conditions their capacity is considerably larger than that of conventional reciprocating mowers, i.e., drum mowers cut some types of crops which are difficult to cut with conventional mowers. Another advantage is that cut crop is normally fluently conveyed in a rearward direction and discharged through the gap between neighboring drums in a well-defined windrow.
As is also known, a conditioner may be attached to a drum mower of the above type. For example, see U.S. Pat. No. 3,751,889 issued on Aug. 14, 1973, and U.S. Pat. No. 3,896,609 issued on July 29, 1975. However, in these known arrangements, the conditioner is cantilevered from the main beam of the mower structure. This arrangement may cause high stresses in critical areas and may also require a drive system of a relatively complicated nature.